Cisco 10000 Series Configuration Manual page 827

U
See unspecified bit rate.
UBR
A QoS class defined by the ATM Forum for ATM networks. UBR allows any amount of data up to a
unspecified bit rate
specified maximum to be sent across the network, but there are not guarantees in terms of cell loss rate
and delay.
The line rate for message or data transfer from the source machine to a destination machine on the
upstream rate
network.
V
See virtual access interface.
VAI
See variable bit rate.
VBR
See variable bit rate-nonreal time.
VBR-nrt
See variable bit rate-real time.
VBR-rt
See virtual circuit.
VC
See virtual channel identifier.
VCI
See virtual channel link.
VCL
A QoS class defined by the ATM Forum for ATM networks. Variable bit rate (VBR) is subdivided into
variable bit rate
a real time (rt) class and nonreal time (nrt) class. See also variable bit rate-nonreal time and variable
bit rate-real time.
A QoS class defined by the ATM Forum for ATM networks. Variable bit rate-nonreal time (VBR-nrt)
variable bit
is used for connections in which there is no fixed timing relationship between samples, but that still
rate-nonreal time
need a guaranteed QoS.
A QoS class defined by the ATM Forum for ATM networks. Variable bit rate-real time (VBR-rt) is used
variable bit rate-real
for connections in which there is a fixed timing relationship between samples.
time
An instance of a unique virtual interface that is created dynamically and exists temporarily. Virtual
virtual access
access interfaces can be created and configured differently by different applications, such as virtual
interface
profiles and virtual private dialup networks (VPDNs).Virtual access interfaces are cloned from virtual
template interfaces.
A 16-bit field in the header of an ATM cell. The virtual channel identifier (VCI), together with the VPI,
virtual channel
is used to identify the next destination of a cell as it passes through a series of ATM switches on its way
identifier
to its destination. ATM switches use the VPI/VCI fields to identify the next network VCL that a cell
needs to transmit on its way to its final destination. The function of the VCI is similar to that of the
DLCI in Frame Relay.
Connection between two ATM devices. A virtual channel connection is made up of one or more VCLs.
virtual channel link
OL-7433-09
Cisco 10000 Series Router Quality of Service Configuration Guide
Glossary
GL-9